Abstract. We propose a new method named compressive structured light for recovering inhomogeneous participating media. Whereas conventional structured light methods emit coded light patterns onto the surface of an opaque object to establish correspondence for triangulation, compressive structured light projects patterns into a volume of participating medium to produce images which are integral measurements of the volume density along the line of sight. For a typical participating medium encountered in the real world, the integral nature of the acquired images enables the use of compressive sensing techniques that can recover the entire volume density from only a few measurements. This makes the acquisition process more efficient and enables reconstruction of dynamic volumetric phenomena. Moreover, our method requires the projection of multiplexed coded illumination, which has the added advantage of increasing the signal-to-noise ratio of the acquisition. Finally, we propose an iterative algorithm to correct for the attenuation of the participating medium during the reconstruction process. We show the effectiveness of our method with simulations as well as experiments on the volumetric recovery of multiple translucent layers, 3D point clouds etched in glass, and the dynamic process of milk drops dissolving in water. 1

for opaque surfaces

In this paper we present a novel method for 3D structure acquisition, based on structured light. Unlike classical structured light methods, in which a static projector illuminates a scene with time-varying illumination patterns, our technique makes use of a moving projector emitting a static striped illumination pattern. This projector is translated at a constant velocity, in the direction of the projector’s horizontal axis. Illuminating the object in this manner allows us to perform a per pixel analysis, in which we decompose the recorded illumination sequence into a corresponding set of frequency components. The dominant frequency in this set can be directly converted into a corresponding depth value. This per pixel analysis allows us to preserve sharp edges in the depth image. Unlike classical structured light methods, the quality of our results is not limited by projector or camera resolution, but is solely dependent on the temporal sampling density of the captured image sequence. Additional benefits include a significant robustness against common problems encountered with structured light methods, such as occlusions, specular reflections, subsurface scattering, interreflections, and to a certain extent projector defocus. 1.

Abstract—We present a flexible interactive 3D morpho-kinematical modeling application for astrophysics. Compared to other systems, our application reduces the restrictions on the physical assumptions, data type and amount that is required for a reconstruction of an object’s morphology. It is one of the first publicly available tools to apply interactive graphics to astrophysical modeling. The tool allows astrophysicists to provide a-priori knowledge about the object by interactively defining 3D structural elements. By direct comparison of model prediction with observational data, model parameters can then be automatically optimized to fit the observation. The tool has already been successfully used in a number of astrophysical research projects.

Abstract. Obscure glass is textured glass designed to separate spaces and “obscure ” visibility between the spaces. Such glass is used to provide privacy while still allowing light to flow into a space, and is often found in homes and offices. We propose and explore the challenge of “seeing through ” obscure glass, using both optical and digital techniques. In some cases – such as when the textured surface is on the side of the observer – we find that simple household substances and cameras with small apertures enable a surprising level of visibility through the obscure glass. In other cases, where optical techniques are not usable, we find that we can model the action of obscure glass as convolution of spatially varying kernels and reconstruct an image of the scene on the opposite side of the obscure glass with surprising detail. 1

We present a novel optical setup and processing pipeline for measuring the 3D geometry and spatially-varying surface reflectance of physical objects. Central to our design is a digital camera and a high frequency spatially-modulated light source aligned to share a common focal point and optical axis. Pairs of such devices allow capturing a sequence of images from which precise measurements of geometry and reflectance can be recovered. Our approach is enabled by two technical contributions: a new active multiview stereo algorithm and an analysis of light descattering that has important implications for image-based reflectometry. We show that the geometry measured by our scanner is accurate to within 50 microns at a resolution of roughly 200 microns and that the reflectance agrees with reference data to within 5.5%. Additionally, we present an image relighting application and show renderings that agree very well with reference images at light and view positions far from those that were initially measured. 1

Many natural phenomena evolve over time — often coupled with a change in their reflectance and geometry — and give rise to dramatic effects in their visual appearance. In computer graphics, such time-varying appearance phenomena are critical for synthesizing photo-realistic images. In computer vision, understanding the formation of time-varying appearance is important for image enhancement and photometric-based reconstruction. This thesis studies time-varying appearance for a variety of natural phenomena — opaque surfaces, transparent surfaces, and participating media — using captured data. We have two main goals: (1) to design efficient measurement methods for acquiring time-varying appearance from the real world, and (2) to build compact models for synthesizing or reversing the appearance effects in a controllable way. We started with time-varying appearance for opaque surfaces. Using a computercontrolled dome equipped with 16 cameras and 160 light sources, we acquired the first database (with 28 samples) of time-and-space-varying reflectance, including a variety of natural processes — burning, drying, decay and corrosion. We also proposed a space time appearance factorization model which disassembles the high-dimensional appearance phenomena